Polar Layered Bismuth‐Rich Oxyhalide Piezoelectrics Bi₄O₅X₂ (XBr, I): Efficient Piezocatalytic Pure Water Splitting and Interlayer Anion‐Dependent Activity

Abstract

Piezocatalytic pure water splitting for H 2 evolution carries the virtues of efficacious utilization of mechanical energy, easy operation, and high value-added products, while lacking desirable piezoelectrics for high chemical energy production. Here, two polar layered bismuth-rich oxyhalides Bi 4 O 5 X 2 (XBr, I) thin nanosheets (≈4 nm) are first exploited as efficient piezocatalysts to be capable of dissociating pure water. The unique asymmetrical layered structures of Bi 4 O 5 X 2 (XBr, I) composed of the interleaved [Bi 4 O 5 ] 2+ layer and double X − ions slabs along the [1 0 1_] orientation cause large intrinsic dipole moment, excellent piezoelectricity and easy deformation. Without any cocatalyst and sacrificial agent, Bi 4 O 5 Br 2 and Bi 4 O 5 I 2 thin nanosheets display remarkable piezocatalytic H 2 production rate of 1149.0 and 764.5 µmol g −1 h −1 , respectively, standing among the best piezocatalysts, accompanied by H 2 O 2 and hydroxyl radicals (•OH) as oxidative products. The smaller radius and higher electronegativity of interleaved Br than I cause a more strongly polar crystal structure in Bi 4 O 5 Br 2 , contributing to the higher piezocatalytic activity compared to Bi 4 O 5 I 2 . This study broadens the scope of piezoelectric materials applied to sustainable energy catalysis by efficiently converting mechanical energy and illustrates the importance of crystal configuration and composition in fabricating efficient piezocatalytic systems.

A novel 1D/2D core/shell CdS@SnS2 heterostructure for efficient piezocatalytic hydrogen evolution and pollutant degradation

“…In this case, the piezoelectric field will make electrons and holes transfer in opposite directions, thereby effectively inhibiting their recombination and allowing more free carriers to be enriched on the catalyst surface to participate in the piezocatalytic reactions. 47–49 Moreover, as revealed by the XPS results, the potential internal electric field is also beneficial for the transfer of electrons and holes mentioned above. As a result, the piezocatalytic performance of the CdS@SnS 2 heterojunction is markedly superior to that of single components.…”

Organic piezocatalyst polyimide: molecular structure tailoring and robust built-in electric field

“…7a. 44 Compared with PM-1 and PM-2, PM-3 holds the largest effective piezoelectric coefficient (9.05 pm V −1 ), which means it exhibits the strongest piezoelectric polarization. It has been confirmed that the catalyst with a higher piezoelectric response could induce a stronger piezoelectric field, thus immensely promoting piezocatalytic activity under an external mechanical force.…”

Harvesting Vibration Energy to Produce Hydrogen Peroxide with Bi3TiNbO9 Nanosheets through a Water Oxidation Dominated Dual-Channel Pathway

“…Therefore, it is hard to scientifically compare these works. The detailed parameters of each work referenced are listed in Table S2. ,,,,− It can be seen that the yield rate of our BTNO is among the highest, showing its advantage for hydrogen peroxide production with only pure water by harvesting vibration energy. Furthermore, it is worth noting that the yield rate of 407.05 μmol·g –1 ·h –1 shown in Figure g was obtained under an ultrasound power of only 50 W, and this is much lower than the reported works wherein the ultrasonic power used is normally in the range of 120–300 W. As discussed in Figure e, the piezocatalytic performance will be enhanced along with increasing the ultrasonic power.…”

“…14 A range of piezocatalysts have been utilized to synthesize H 2 O 2 , including g-C 3 N 4 , 9 metal oxides such as BaCaZrTi perovskite oxide, 4 BaTiO 3 , 15 (Bi 0.5 Na 0.5 )-TiO 3 , 16 and NaNbO 3 . 17 Bismuth layered compounds, which are composed of [Bi 2 O 2 ] 2+ slices and interleaved anions and/or anionic groups, have also demonstrated their applications in H 2 O 2 preparation under the mechanical vibration such as Bi 4 Ti 3 O 12 , 18,19 BiOCl, 20 Bi 4 O 5 Br 2 , 21 etc. The application of bismuth layered compounds as piezo-catalysts is related to their noncentrosymmetric characteristics.…”

“…Bismuth layered compounds, which are composed of [Bi 2 O 2 ] 2+ slices and interleaved anions and/or anionic groups, have also demonstrated their applications in H 2 O 2 preparation under the mechanical vibration such as Bi 4 Ti 3 O 12 , , BiOCl, Bi 4 O 5 Br 2 , etc. The application of bismuth layered compounds as piezo-catalysts is related to their noncentrosymmetric characteristics.…”